Great report, Jeff. Many thanks.
Can you please take a good photo of one of these MOVs on a pole so that
we know what they look like? Dave, NK7Z and I can post it on our websites.
MOVs can be pretty nasty devices. They are a train wreck on branch
circuits in surge suppressors, where they are likely to CAUSE
destructive failures when equipment plugged into protectors at different
locations are connected together. And as they absorb charges over time,
they degrade, but it takes a while before they fail destructively. I
suspect, but do not know, that in that intermediate state is when they
may be causing the noise you've documented.
73, Jim K9YC
On 1/10/2019 10:12 PM, Jeff Blaine wrote:
About 10am the noise went silent. I called the guy and he told me
they checked out the pole with the caps on it first, and then went
over and pulled the MOVs on the NW pole. I guess the lesson of the
MOVs as culprit was not quite learned - but after the 2nd pole I think
the fellow was a believer.
Much greatness was expressed. And I've enjoyed the quiet conditions
since! Many thanks to the local that helped me out on the
identification and to the power company who had no problem fixing the
problems once they were convinced the proper pole was identified.
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
On 23-Dec-18 8:15 PM, Jeff Blaine wrote:
Turns out this was not a Christmas light display, but apparently is a
MOV on a pole in front of the guy's house.
Diagnosis and tracking involved driving around looking at signal
levels on a PL660 SWL. Then looking at higher and higher
frequencies to try to localize. I still could not identify a
particular pole though.
Next step was to use a MFJ VHF noise detector which allowed me to
localize down to a 4 pole location over a 200' area. The local power
company was not motivated to go out and check into it with this level
of diagnosis.
So a buddy K3PA brought over his industrial stuff today and we got it
nailed down to a single pole which has a pair of MOV. Tools used in
that were a 440 yagi with a Yaesu FT817, then a confirmation with a
Radar Engineers Ultrasonic/UHF detector. The guy had an ultrasonic
dish but we did not need to use it.
The power company was updated with my single pole diagnosis and today
promised they would contact me for repair details in 48 hours. That
would be great and just in time for the SP next weekend!
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
On 08-Dec-18 12:15 PM, Jeff Blaine wrote:
I'm going to go see a neighbor today who always has a great looking
display about this time each year. This go around, he's expanded to
even more and better looking stuff.
The problem is when it fires up the noise floor from 160 up through
10m bumps up a few dB to a few tens of dB. And the guy is about 1/2
mile away!
Looks like the primary energy point is about 6 Mhz which was a
surprise. Very wide banded. And amazingly strong.
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
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